agent/consul: Intention.Get endpoint

agent/consul/intention_endpoint.go

@@ -65,6 +65,37 @@ func (s *Intention) Apply(
 	return nil
 }
 
+// Get returns a single intention by ID.
+func (s *Intention) Get(
+	args *structs.IntentionQueryRequest,
+	reply *structs.IndexedIntentions) error {
+	// Forward if necessary
+	if done, err := s.srv.forward("Intention.Get", args, args, reply); done {
+		return err
+	}
+
+	return s.srv.blockingQuery(
+		&args.QueryOptions,
+		&reply.QueryMeta,
+		func(ws memdb.WatchSet, state *state.Store) error {
+			index, ixn, err := state.IntentionGet(ws, args.IntentionID)
+			if err != nil {
+				return err
+			}
+			if ixn == nil {
+				return ErrQueryNotFound
+			}
+
+			reply.Index = index
+			reply.Intentions = structs.Intentions{ixn}
+
+			// TODO: acl filtering
+
+			return nil
+		},
+	)
+}
+
 // List returns all the intentions.
 func (s *Intention) List(
 	args *structs.DCSpecificRequest,

agent/consul/intention_endpoint_test.go

@@ -2,6 +2,7 @@ package consul
 
 import (
 	"os"
+	"reflect"
 	"testing"
 
 	"github.com/hashicorp/consul/agent/structs"
@@ -37,7 +38,29 @@ func TestIntentionApply_new(t *testing.T) {
 		t.Fatal("reply should be non-empty")
 	}
 
-	// TODO test read
+	// Read
+	ixn.Intention.ID = reply
+	{
+		req := &structs.IntentionQueryRequest{
+			Datacenter:  "dc1",
+			IntentionID: ixn.Intention.ID,
+		}
+		var resp structs.IndexedIntentions
+		if err := msgpackrpc.CallWithCodec(codec, "Intention.Get", req, &resp); err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		if len(resp.Intentions) != 1 {
+			t.Fatalf("bad: %v", resp)
+		}
+		actual := resp.Intentions[0]
+		if resp.Index != actual.ModifyIndex {
+			t.Fatalf("bad index: %d", resp.Index)
+		}
+		actual.CreateIndex, actual.ModifyIndex = 0, 0
+		if !reflect.DeepEqual(actual, ixn.Intention) {
+			t.Fatalf("bad: %v", actual)
+		}
+	}
 }
 
 func TestIntentionList(t *testing.T) {

agent/structs/intention.go

@@ -99,3 +99,20 @@ type IntentionRequest struct {
 func (q *IntentionRequest) RequestDatacenter() string {
 	return q.Datacenter
 }
+
+// IntentionQueryRequest is used to query intentions.
+type IntentionQueryRequest struct {
+	// Datacenter is the target this request is intended for.
+	Datacenter string
+
+	// IntentionID is the ID of a specific intention.
+	IntentionID string
+
+	// Options for queries
+	QueryOptions
+}
+
+// RequestDatacenter returns the datacenter for a given request.
+func (q *IntentionQueryRequest) RequestDatacenter() string {
+	return q.Datacenter
+}